Radiator Tube with Angled Flow Passage

ABSTRACT

A radiator tube. Implementations of a radiator tube may include a tube body with external sides including an internal flow passage defined by the tube body oriented obliquely with respect to one or more external sides of the tube body.

CROSS REFERENCE TO RELATED APPLICATIONS

This document claims the benefit of the filing date of U.S. Provisional Patent Application 60/866,151 entitled “Skewed Rectangular Tube Solution for Spacecraft Radiator Micro Meteoroid and Orbital Debris (MMOD) Hardening” to Grant Allan Anderson, which was filed on Nov. 16, 2006, the disclosure of which is hereby incorporated entirely herein by reference.

BACKGROUND

1. Technical Field

Aspects of this document relate generally to radiator tubes used for heat transfer.

2. Background Art

Radiators have been conventionally used to transfer heat between a fluid at one temperature to a fluid at a second temperature. Conventional radiators utilize a variety of factors such as geometry, flow orientation, flow alignment, and material characteristics to regulate the rate and quantity of heat transfer that occurs. Many conventional radiators involve flowing fluid through tubes while heat from the environment either enters the tubes and heats the flowing fluid or leaves the tubes and cools the flowing fluid.

SUMMARY

Implementations of a radiator tube may include a tube body with external sides. The tube body with external sides may include an internal flow passage defined by the tube body that is oriented obliquely with respect to one or more of the external sides of the tube body.

Implementations of a radiator tube may also feature a rectangular tube body with external sides. The rectangular tube body with external sides may include a rectangular internal flow passage defined by the rectangular tube body that is oriented obliquely with respect to one or more of the exterior sides of the rectangular tube body.

Implementations of radiator tubes may include one, all, or some of the following:

The tube body or rectangular tube body may be coupled to a facesheet.

Implementations of a spacecraft radiator system may include a plurality of tube bodies having an internal flow passage defined by the tube body that is oriented obliquely with respect to one or more exterior sides of the tube body. At least one facesheet in thermal communication with an external low-temperature radiative environment may be coupled to the plurality of tube bodies.

Implementations of radiator tubes or spacecraft radiator systems may include one, all or some of the following:

The tube body may be rectangular. The internal flow passage may be rectangular. A short side of the tube body may be coupled to a facesheet. The rectangular internal flow passage may have an aspect ratio of at least about 2.5:1. The rectangular internal flow passage may be oriented obliquely with respect to one or more external sides of the tube body at an angle between on of about 0.01 to 89.99 degrees and about 90.01 to 179.99 degrees.

The foregoing and other aspects, features, and advantages will be apparent to those artisans of ordinary skill in the art from the DESCRIPTION and DRAWINGS, and from the CLAIMS.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will hereinafter be described in conjunction with the appended drawings, where like designations denote like elements, and:

FIG. 1 shows a cross-section through a radiator tube;

FIG. 2 shows the position of the internal flow passage in relation to the tube body with an angle A to the bottom side of the tube body;

FIG. 3 is prior art view of a radiator tube geometry;

FIG. 4 is a prior art view of a radiator tube geometry.

DESCRIPTION

This disclosure, its aspects and implementations, are not limited to the specific components or assembly procedures disclosed herein. Many additional components and assembly procedures known in the art consistent with the intended radiator tube and/or assembly procedures for a radiator tube will become apparent for use with particular implementations from this disclosure. Accordingly, for example, although particular implementations are disclosed, such implementations and implementing components may comprise any shape, size, style, type, model, version, measurement, concentration, material, quantity, and/or the like as is known in the art for such radiator tubes and implementing components, consistent with the intended operation.

Structure.

Referring to FIG. 1, a particular implementation of a radiator tube is illustrated. The radiator tube 2 includes an internal flow passage 4 and a tube body 6. The aspect ratio of the internal flow passage 4 (the ratio between the width 5 of the flow passage 4 to the height 7 of the flow passage 4) is greater than 2.5:1. Implementations of radiator tubes 2 described in this document may utilize flow passages 4 with aspect ratios of about 2.5:1 or greater. The radiator tube is coupled to a facesheet 8 which may be in thermal communication with the outside environment 10. In the implementation illustrated in FIG. 1, the radiator tube 2 is rectangular and is coupled to the facesheet 8 along the rectangular tube's short side. This environment may be, in particular implementations, an external low-temperature radiative environment 10, such as space.

Referring to FIGS. 1, 3, and 4, radiator tubes may be constructed utilizing flow passages of different shapes. Heat transfer characteristics of internal, laminar fluid flow are governed by the Nusselt number which is determined by the tube geometry, the tube materials, and the physical properties of the working fluid passing through the tube. A circular radiator tube geometry, like that shown in FIG. 4, lends itself to the most efficient use of area and yields a maximum Nusselt number. Nevertheless, a rectangular radiator tube with an aspect ratio of 2.5:1 or more, like that shown in FIG. 3, may match or exceed the heat transfer capability of a circular radiator tube. While a round radiator tube may not provide as much contact area with the facesheet to which it is attached as a rectangular radiator tube, the specific geometry of a round radiator tube allows for additional heat transfer characteristics that overcome the limited contact area with the radiator panel or facesheet. Nevertheless, as the aspect ratio of a rectangular radiator tube approaches 2.5:1, its heat transfer characteristics will approach those of a circular radiator tube.

Referring to FIGS. 1 and 2, the longest dimension of the flow passage 4 is not parallel to the facesheet 8, unlike the prior art tube shown in FIG. 3. As illustrated, the angle A of the internal flow passage 4 with respect to one or more external sides 12 of the tube body 6 may range from 0.01 to 179.99 degrees, excluding 90.00 degrees. Radiator tubes utilizing flow passages 4 angled relative to an external side 12 of the tube body 6 may exhibit heat transfer characteristics like those of a circular tube like that illustrated in FIG. 4 while reducing the amount of the flow passage 4 oriented in a plane parallel to the facesheet 8. The external side 12 may be a short side of the tube body 6.

The radiator tube 2 illustrated is shown formed as a single piece. In other implementations the radiator tube 2 may be formed of any number of pieces coupled together. Implementations of a radiator tube 2 may be formed using many method known to those of ordinary skill in the art, including, by non-limiting example, casting, extrusion, welding, drawing, forging, and the like.

Use.

Referring to FIG. 1, the operation of a radiator tube 2 will be described. A working cooling fluid is circulated through the flow passage 4 within the tube body 6 through, by non-limiting example, a pump, convective flow, or gravity. The working cooling fluid may draw away heat from a heat source as the fluid circulates in the internal flow passage 4 and conduct the heat to a facesheet 8, which then radiates the heat to an external low-temperature radiative heat transfer environment 10, such as space.

In other particular implementations, the working cooling fluid may receive heat from a higher temperature reservoir in fluid communication with the facesheet 8 through conductive, convective, or radiative heat transfer and transfer that heat to a heat sink in fluid connection with the working cooling fluid. In some implementations, a facesheet 8 may not be used, but the working cooling fluid may receive or reject heat to a fluid directly in contact with the external surfaces 12 of the radiator tube 2 in, by non-limiting example, cross-flow, parallel-flow, or concentric counterflow flow orientations. Particular implementations of a radiator tube 2 may also be used in a wide variety of applications, such as, by non-limiting example, vehicle radiators, vacuum pressure vessel cooling/heating systems, building air conditioners, cooling plates, hot plates, and other heating and cooling systems or appliances.

Particular implementations of a radiator tube 2 may be particularly useful in spacecraft radiator applications because the exploration of space poses a number of unique risks unequalled on Earth. In particular, there exist large quantities of rapidly moving particles of varying sizes in the immediate vicinity of Earth and in the Earth's orbit. Some of these rapidly moving particles are of man-made origin and others are naturally occurring particles. Collectively, these rapidly moving particles are referred to as Micrometeoroids and Orbital Debris (MMOD). The likelihood of an MMOD impacting a spacecraft is inversely proportionate to the size of the MMOD. That is, the smaller an MMOD, the greater the likelihood that it will impact a spacecraft. Conversely, the larger an MMOD, the less the likelihood that it will impact a spacecraft. Nevertheless, many MMOD, large or small, have sufficient momentum to pierce spacecraft components. In some cases, MMOD impacts upon spacecraft can be merely annoying, such as when an MMOD impacts a non-critical system of a spacecraft. In other instances, an MMOD impact upon a spacecraft can be catastrophic, such as when a critical system is impacted.

One critical system that could fail due to an MMOD impact is the spacecraft radiator system used for heat rejection. Many spacecraft have thermal power plants, such as nuclear reactors, to satisfy the power requirements of spacecraft instruments and systems. Thermal power plants such as nuclear reactors generate heat which must be dispersed in order to ensure proper continued operation. Spacecraft radiator systems have been used to dissipate the heat generated by spacecraft thermal power plants. Spacecraft radiator systems have used radiator tubes carrying a circulating working fluid. The working fluid draws away the heat generated by the thermal power plant and conducts it into a radiator panel or facesheet which rejects the heat by radiation into space.

In the event that an MMOD were to pierce a radiator tube, a large portion of the radiator system's heat rejection capability would be lost. The prevalence of MMOD in space and the catastrophic consequences possible from a MMOD strike make protection from impacting space debris a high priority for spacecraft radiator engineers.

Referring to FIGS. 1 and 2, by rotating a rectangular internal flow passage 4, the projected area at risk for an MMOD impact through the facesheet 8 is diminished without reducing the heat transfer characteristics of the radiator tube 2. This is because the portion of the internal flow passage 4 oriented parallel to the facesheet 8 is reduced (as can be seen in comparison with the rectangular flow passage shown in FIG. 3). Therefore, an angled rectangular internal flow passage with an aspect ratio of 2.5:1 or greater may have heat transfer characteristics equal to or better than a round radiator tube, while simultaneously exposing a smaller area of the tube to potential MMOD strikes.

It will be understood that implementations are not limited to the specific components disclosed herein, as virtually any components consistent with the intended operation of a method and/or system implementation for radiator tubes may be utilized.

In places where the description above refers to particular implementations of radiator tubes, it should be readily apparent that a number of modifications may be made without departing from the spirit thereof and that these implementations may be applied to other than spacecraft radiator tubes. The accompanying claims are intended to cover such modifications as would fall within the true spirit and scope of the disclosure set forth in this document. The presently disclosed implementations are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the disclosure being indicated by the appended claims rather than the foregoing description. All changes that come within the meaning of and range of equivalency of the claims are intended to be embraced therein.

The embodiments and examples set forth herein were presented in order to best explain the present invention and its practical application and to thereby enable those of ordinary skill in the art to make and use the invention. However, those of ordinary skill in the art will recognize that the foregoing description and examples have been presented for the purposes of illustration and example only. The description as set forth is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the teachings above without departing from the spirit and scope of the invention. 

1. A radiator tube comprising: a tube body with external sides; and an internal flow passage defined within the tube body and oriented obliquely with respect to one or more of the external sides of the tube body.
 2. The radiator tube of claim 1, wherein the tube body is coupled to a facesheet.
 3. The radiator tube of claim 2, wherein the tube body is substantially rectangular.
 4. The radiator tube of claim 3, wherein a short side of the tube body is coupled to the facesheet.
 5. The radiator tube of claim 2, wherein the internal flow passage is substantially rectangular.
 6. The radiator tube of claim 1, wherein the tube body is substantially rectangular.
 7. The radiator tube of claim 1, wherein the internal flow passage is substantially rectangular.
 8. The radiator tube of claim 1, wherein the internal flow passage has an aspect ratio of at least about 2.5:1.
 9. The radiator tube of claim 1, wherein the internal flow passage is oriented obliquely between one of: about 0.01 to 89.99 degrees; and about 90.01 to 179.99 degrees.
 10. A radiator tube comprising: a rectangular tube body with external sides; and a rectangular internal flow passage defined within the tube body and oriented obliquely with respect to one or more of the exterior sides of the tube body.
 11. The radiator tube of claim 10, wherein the rectangular internal flow passage has an aspect ratio of at least about 2.5:1.
 12. The radiator tube of claim 10, wherein the rectangular tube body is coupled to a facesheet.
 13. The radiator tube of claim 10, wherein a short side of the rectangular tube body is coupled to the facesheet.
 14. The radiator tube of claim 10, wherein the rectangular internal flow passage is oriented between one of: about 0.01 to 89.99 degrees; and about 90.01 to 179.99 degrees.
 15. A spacecraft radiator system comprising: a plurality of tube bodies, each tube body comprising an internal flow passage defined within the tube body and oriented obliquely with respect to one or more exterior sides of the tube body; and at least one facesheet in thermal communication with an external low-temperature radiative environment coupled to the plurality of tube bodies.
 16. The spacecraft radiator system of claim 15, wherein the plurality of tube bodies are substantially rectangular.
 17. The spacecraft radiator system of claim 15, wherein the internal flow passage in each of the plurality of tube bodies is substantially rectangular.
 18. The spacecraft radiator system of claim 17, wherein the rectangular internal flow passages of the plurality of tube bodies have an aspect ratio of at least about 2.5:1.
 19. The spacecraft radiator system of claim 16, wherein the plurality of tube bodies each comprise a short side and the short side of each of the plurality of tube bodies is coupled to the at least one facesheet.
 20. The spacecraft radiator system of claim 15, wherein the rectangular internal flow passage is oriented obliquely between one of: about 0.01 to 89.99 degrees; and about 90.01 to 179.99 degrees. 